Original issue, US Army Technical Manual, 60 pages, size is 6" x 9", stapled, dated 18 December 1957.  This is not a commercial copy or print but an original issue government print issued in 1957 and republished in 1958.  This publication is titled TM 9-1901-1, Ammunition for Aircraft Guns.  Publication is designed to provide information and instructions for general and technical information concerning ammunition for aircraft guns (.50 machine guns and 20-mm guns).  Very well illustrated using photographs and detailed line drawings.